org.graalvm.nativeimage.c.function.CEntryPointLiteral Maven / Gradle / Ivy
/*
* Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* The Universal Permissive License (UPL), Version 1.0
*
* Subject to the condition set forth below, permission is hereby granted to any
* person obtaining a copy of this software, associated documentation and/or
* data (collectively the "Software"), free of charge and under any and all
* copyright rights in the Software, and any and all patent rights owned or
* freely licensable by each licensor hereunder covering either (i) the
* unmodified Software as contributed to or provided by such licensor, or (ii)
* the Larger Works (as defined below), to deal in both
*
* (a) the Software, and
*
* (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
* one is included with the Software each a "Larger Work" to which the Software
* is contributed by such licensors),
*
* without restriction, including without limitation the rights to copy, create
* derivative works of, display, perform, and distribute the Software and make,
* use, sell, offer for sale, import, export, have made, and have sold the
* Software and the Larger Work(s), and to sublicense the foregoing rights on
* either these or other terms.
*
* This license is subject to the following condition:
*
* The above copyright notice and either this complete permission notice or at a
* minimum a reference to the UPL must be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package org.graalvm.nativeimage.c.function;
import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;
import org.graalvm.nativeimage.impl.CEntryPointLiteralCodePointer;
/**
* A function pointer to an {@link CEntryPoint entry point method} that can be, for example, handed
* out to C code so that C code can call back into Java code. The method that is referred to must be
* annotated with {@link CEntryPoint}, which imposes certain restrictions.
*
* The actual value of the function pointer is only available at run time. To prevent accidental
* access to it during native image generation, the actual {@link #getFunctionPointer() function
* pointer} is encapsulated in this class. The call to {@link #getFunctionPointer()} fails with an
* exception during native image generation.
*
* Instances of this class can only be created during native image generation. It is not possible to
* look up a function by name at run time. The intended use case is therefore as follows:
*
*
* // Function that is externally accessible
* @CEntryPoint
* static int myFunction(IsolateThread thread, int x, int y) {
* ...
* }
*
* // Invocation interface (for calls from Java, otherwise CFunctionPointer suffices)
* interface MyFunctionPointer extends FunctionPointer {
* @InvokeCFunctionPointer
* int invoke(IsolateThread thread, int x, int y);
* }
*
* // Function pointer literal
* public static final CEntryPointLiteral<MyFunctionPointer> myFunctionLiteral = CEntryPointLiteral.create(MyClass.class, "myFunction", new Class[]{IsolateThread.class, int.class, int.class});
*
* // Call from Java
* void caller() {
* MyFunctionPointer fp = myFunctionLiteral.getFunctionPointer(); // entry point, could be returned to C code
* int fiftyeight = fp.invoke(CurrentIsolate.getCurrentThread(), 47, 11);
* }
*
*
* @since 19.0
*/
public final class CEntryPointLiteral {
/* Field is accessed using alias. */
@SuppressWarnings("unused") //
private CFunctionPointer functionPointer;
private CEntryPointLiteral(Class definingClass, String methodName, Class... parameterTypes) {
this.functionPointer = new CEntryPointLiteralCodePointer(definingClass, methodName, parameterTypes);
}
/**
* Creates a new function pointer to an entry point.
*
* @since 19.0
*/
@Platforms(Platform.HOSTED_ONLY.class)
public static CEntryPointLiteral create(Class definingClass, String methodName, Class... parameterTypes) {
return new CEntryPointLiteral<>(definingClass, methodName, parameterTypes);
}
/**
* Returns the function pointer to the entry point.
*
* @since 19.0
*/
public T getFunctionPointer() {
throw new IllegalStateException("Cannot invoke method during native image generation");
}
}